Engines are often equipped with balance shafts rotatably connected to and parallel with the engine crankshaft via a chain and sprocket or a gear train. The balance shafts have counterweights that help to counter vibrational forces created by engine pistons which rotate the crankshaft. The balance shafts are typically housed in the oil pan connected to the engine block. A balance shaft housing surrounds the balance shafts within the oil pan to minimize contact of the rotating countershafts with the oil. When the engine is off for an extended period of time, the housing tends to fill with oil contained within the oil pan. When the engine is started, and the balance transfer shafts begin rotating, oil collected within the housing around the balance shafts must be expelled in order to reduce oil aeration and losses due to resistance to rotation. A balance shaft housing that affords expedient expulsion of oil while being easy to assemble and of relatively low cost is desired.